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1. Field of the Invention
This invention relates to the automatic detection and identification of a tire with low pressure and a notification device to alert the user of the situation.
2. Description of Related Art
Low tire pressure increases the tread wear and shortens the effective life of a tire. If the tire pressure is sufficiently low, a decrease in steering control will occur which may lead to an accident. A significant loss of tire pressure may cause the tire to rupture, commonly known as a tire xe2x80x9cblowoutxe2x80x9d, which leads to a sudden loss of tire pressure with an immediate effect on steering control thus increasing the risk of an accident.
At the present time, it is incumbent upon the user of a vehicle employing tires to remember to manually self-check the tire pressure using one of the commonly available tire pressure gauges. Unfortunately, tire pressure is frequently not checked because the person forgets, does not have access to a working tire gauge, is physically unable to check the tire pressure, or for other reasons. Even if the tire pressure is routinely checked on a predetermined schedule, an acute event, such as a tire puncture from hitting road debris, driving conditions, temperature, vehicle load or other factors may affect the tire pressure and go unnoticed by the user of the vehicle until an attendant problem, as described above, occurs.
This invention relates generally to an improvement in the means for detecting a change in slope of a member relative to a reference and the notification of the user. The simplicity of use and the commercial practicality of manufacture of the device is a material advantage over existing systems.
Slope detectors or inclinometers have been previously used as flat tire detectors and have been combined with notification devices to inform the vehicle operator of a loss in tire pressure. One such device incorporates a mercury tilt switch. A pool of mercury is enclosed in a housing and a change in the slope of the housing causes the mercury to shift thus closing a pair of electrical contacts. The closure of the contacts activates a notification device to indicate a loss of tire pressure.
The prior art devices systems were not without drawbacks including spurious indication of a flat tire such as occurs when a tire hits a pothole or were impractical to use, inexpedient or not commercially feasible to.manufacture. It is, therefore, to the effective resolution of the aforementioned problems and shortcomings that the present invention is directed.
Accordingly, it is an object of this invention to provide a device to automatically identify a tire with low pressure.
It is another object of this invention to provide an automatic system where the user of a device with tires is notified when the tire pressure is below the preset recommended minimum.
It is still another object of this invention to provide a stable support such that the devices may be easily and firmly affixed to the vehicle.
The foregoing objects are achieved and the foregoing problems are solved in one illustrative embodiment of the invention in which inclinometers, such as, but not limited to, mercury tilt switches are preferably placed at right angles to each other and are placed at least substantially parallel to the horizontal plane. The contacts of the tilt switch can be at least substantially vertically oriented to further reduce spurious activation. The tilt switches are preferably connected to a timing circuit such that only a preset time duration activation will result in a signal being sent to a notification device, such as a light, sound, or other indication member or device.
In one embodiment of the device, four tilt switches are employed, two are preferably oriented at least substantially perpendicular to the other two and all are in the same plane. The contacts of each switch are at the opposite end of each of the other switches. As an example, the activation of the contacts on the right and upper most contacts will indicate a deflation of the right front tire. Similarly, the activation of the contacts on the left and lower most contacts will indicate a deflation of the left rear tire. The tilt switches are preferably wired to, or otherwise in communication with time delay/circuit, such as a two minute time delay which would indicate that the contacts were closed for preferably a two minute interval before a light, sound etc. would activate.
The two minute interval is chosen by way of example and is not considered limiting and other time intervals can be chosen and are also considered within the scope of the invention. The preferred time delay should help prevent an acute change, like a vehicle hitting a curve or pothole, from spuriously notifying the user that a flat tire has occurred. In the preferred embodiment, the detection and notification device are enclosed in a hard case which is affixed to the front windshield or front dashboard by suction cup, Velcro, adhesive or other means. The deflation of a tire would activate a light, sound or other notification device indicating which tire had deflated. Alternatively, the device may be affixed to the roof of the vehicle and the notification device would be a sound drawing the attention of the driver to the possibility that a tire had deflated. In another variation of the device, the detection device may be affixed to the roof of the vehicle or another location and the notification device placed within visualization of the driver, such as in or on the front dashboard or windshield. The devices may be connected and/or communicate by wires, infrared, remote control or another method. The power of the device may be internal battery, the vehicle""s cigarette light or other auxiliary power port or the vehicle""s electrical system depending upon the location of the device.
In another embodiment of the invention, two devices, each consisting of three tilt switches are connected to a timing circuit and notification device. Each device consists of two at least substantially parallel switches with the contacts at opposing ends and one tilt switch oriented at least substantially perpendicular to the other two. One device would be placed in the front of the vehicle, as described above, the other on the rear window or ledge. The front device will contain a tilt switch with the perpendicular switch oriented with a front facing contact, the rear device will contain the perpendicular switch oriented with a rear facing contact. The front device will assess the deflation of the front two tires, the rear device will assess the deflation of the rear two tires. A timing circuit is again preferably employed to reduce spurious notification as would take place if a tire hit a pothole. The two devices could be wired together, or alternatively, individually provide a signal to the notification device. The notification would be activated by wire, infrared or a radio controlled signal activating a light or sound or other means. The power for the devices may be battery or wired into the vehicle""s electrical system.
In another embodiment of the device, four separate sensors, each containing two tilt switches oriented at least substantially perpendicular to one another with the contacts closest to each switch are used. They may be placed on the vehicle""s axle, inside the body near the wheel, in the front and rear light assemblies, in the engine compartment and the trunk, in the passenger compartment, or in another location, the goal being that two front sensors reflect the inflation of the two front tires and the two back sensors reflect the inflation of the two rear tires. The timing circuit may be directly attached to the sensors or connected by wire, or other communication means, to the sensors and be incorporated within the notification device. Alternatively, the sensors may be connected by remote radio control. The power supply may be battery or wired into the vehicle""s electrical system.
In accordance with these and other objects which will become apparent hereinafter, the instant invention will now be described with particular reference to the accompanying drawings.